An actinomycete, strain BC 44T-5(T), with the ability to degrade poly(d-3-hydroxybutyrate) was isolated from a soil sample collected from Miaoli County, Taiwan. The isolate displayed substrate mycelia and short spore chains were borne on the aerial mycelia. Spores were non-motile, round, 1 mum in diameter and spiny. The aerial spore mass was blue. Strain BC 44T-5(T) had meso-diaminopimelic acid as the diagnostic diamino acid of the cell-wall peptidoglycan. Whole-cell sugars of the novel strain were identified as glucose, galactose and madurose. Diphosphatidylglycerol and phosphatidylinositol were detected. The predominant menaquinones were MK-9(H(4)) and MK-9(H(2)). Mycolic acids were not detected. Major cellular fatty acids were iso-C(16 : 0) (14.82 %), C(16 : 0) (14.63 %), C(17 : 0) (13.79 %) and 10-methyl-C(17 : 0) (23.77 %.) The DNA G+C content of strain BC 44T-5(T) was 70.6 mol%. On the basis of phenotypic and genotypic data, it is proposed that strain BC 44T-5(T) (=FIRDI 002(T)=BCRC 16873(T)=LMG 24335(T)) should be classified as the type strain of a novel species of the genus Actinomadura, Actinomadura miaoliensis sp. nov.